Your attention is drawn to the Examination Conventions in the on-line Undergraduate Course Handbook and on the Departmental web page. Since these are rather long, this is a brief resume of the most important points, and answers the most frequent questions.
The Prelims examinations in June consist of 4 papers. The structure of each is slightly different and will be the same as last year.
You must pass all four papers and complete the practical requirement (including IT) in order to qualify to continue in the second year. There is a resit examination in September.
The pass mark on each paper is 40%, and a distinction will be awarded for high overall averages, probably 70% or higher, but the exact cut-off will be decided by the examiners.
Examiners use their academic judgement in marking. They are not looking for a specific answer in a specific form, and may award marks for incorrect answers if they are reasonable.
Examiners will follow through answers, credit may be given for correct arguments based on an incorrect earlier answer. The way this is dealt with is a matter of judgement and will depend on the gravity of the original error, e.g. how impossible the incorrect answer is. Examiners do not award negative marks for poor answers.
Read the question carefully and answer the question set, not the one you would have liked.
You are strongly advised not to attempt more questions than required, your time is much better spent in checking and correcting your answers. You can only get credit for the required number of questions.
Long questions are generally set in such a way that if you get stuck on one part you can continue with the question. You should be aiming to amass as many marks as possible, and it is foolish to give up on a question because you have got stuck on an early part, when you could complete the rest.
If a part is taking too much time, you should consider moving on and continue with other parts; if you have time at the end you can return to complete it. Remember that you may answer questions in any order, even for compulsory sections.
In Physical Chemistry the most common errors are unit errors. Get into the habit of including units in all your calculations to avoid this. Your answer is not correct without them.